In this Bi-Centric retrospective study, we could conclude that TMVIV/TMVIR can be a safe and effective therapeutic modality in patients with prior mitral valve surgery. Our statistical data could not be compared with these of published recently in January 2021 because of the size of cohort group (857 patients) and the multicentric design [5]. Our cohort group is smaller and bi-centric. This would add for the weight of our study in one aspect which is the common standardized pre, intra and postoperative protocols, since the same surgeon was responsible for these procedures in the 2 hospitals and he implemented the same management protocols as a routine.
In comparison to Long et al., who published his paper in 2018, we have contrary study groups [4]. We have more patients operated in transaapical approach than in transseptal approach. This could be explained through the fact that we have a reasonable experience in transapical approaches because we operated up to 50% of our TAVI patients until 2012 as transapical. That’s why we could operate our transcatheter mitral valve procedures only in transapical approach until our Mitraclip team was able to build up reasonable experience in septal puncture by 2017. This explains why we did not have any conversion rate due to failure to retrograde passing the valve. Our retrograde passing protocol was as follows; at first, a straight Teflon wire was used and if failed, we use Terumo straight wire (sometimes under rapid pacing). We had to use the Agillis sheath in one patient as a third option.
The reason that we have the majority of our patients are with prior implanted mitral rings is that we are considered as a referral center in East Germany for Minimmally invasive mitral valve repair (Ring + artificial loops). As a matter of fact, the TMVIR cases are more challenging and more complex cases when compared to TMVIV cases. In TMVIR cases, we have to study the detailed anatomy of the LVOT and Anterior mitral leaflet to avoid LVOT obstruction.
Concerning the incidence of LVOT obstruction, we reported one patient with documented intraoperative LVOT obstruction who died on the fifth postoperative day. Long et al series documented 2 cases out of 24 patients [4]. We could admit that our postoperative diagnostic tool for LVOT obstruction (Only Echocardiography) was less accurate than what was implemented in Ashleigh long series (CT). This means we could have missed diagnosing this phenomena in our cohort series and if we had done CT routinely, we could have found out more patients with this complication.
Hu et al reported >12% of the patients more than mild mitral regurge (Paravalvular) postoperatively [3]. We reported only one patient with moderate paravalvular leakage in our series with prior mitral annuloplasty ring. This could be explained that all of our patients had previously a semi rigid complete ring (physio 2 ring) which is known to have lower chance of paravalvular leak because it will be changed in to a circular ring by the implanted Edwards sapien TAVI valve.
Our average blood loss is significantly more than what is reported in Ashleigh series. This could be explained may be through the fact that we never stop the anticoagulation medications preoperatively. On the other hand, we lie far beyond the drainage loss reported by Mehaffey HJ who published the results of redo surgical mitral valve surgery and published in 2018 [6]. This adds to our philosophy that Transcatheter approaches in such cases could be safer concerning bleeding. Length of ICU and hospital stay in our study coincides with most of the paper published in this domain. In most of the centers, these procedures are whether done under local anesthesia or general anesthesia with light sedation where the patient is extubated immediately on the operating table. Anemia postoperatively was not a studied parameter in many of the studies in this domain. In our study, we reported 2 patients (5.5%) with hemolytic anemia postoperatively who were on warfarin therapy preoperatively. Our results coincides with Coylewright M who reported anemia in 6.1% of his study population [7]. We coincide together in not stopping the anticoagulants preoperatively as well, which may explain our coincidence. Our results concerning mean transvalvular gradient postoperatively, showed lower gradients in comparison to Eleid MF [8]. This could be explained throughout that most of our patients were with prior implanted semi rigid complete ring and we intended to oversize in most of our patients. Fortunately, despite oversizing, we found out no patients with new severe paravalvular leakage due to ring deformation or dehiscence. Our total operative time was shorter than Long et al [4]. This is probably because of the common same operator in all of the 36 cases (routine maintained) or may be because we did not perform valvoplasty in any of our cases or due to the routine usage of Agilis sheath for valve passage in transseptal cases which might save few minutes.